1. Field of the Invention
The present invention relates to an apparatus for printing an image on a medium.
2. Description of the Related Art
A printing station is known in the art that receives an image signal on a serial interface containing information about an image having for example one or more ASCII characters to be printed on a given medium, that rasterizes the image signal to create a bitmap of the one or more ASCII characters with a rasterizer board, and that remaps a rasterized image signal with pen driver boards for printing the image with Hewlett Packard pens on the given medium. The printing station has a pen housing for housing the pen driver boards and the Hewlett Packard pens.
One disadvantage of the known printing station is that it does not have a number of standard interfaces, and did not daisy chain multiple imagers.
Another disadvantage of the known printing station is that the rasterizer board is remote from the pen housing and not arranged therein. This results in an electrical noise being introduced into the rasterized image signal transmitted along a cable connecting the rasterizer board to the pen driver boards. The rasterizer board cannot be arranged in the pen housing because it is configured from a standard off-the-shelf printed circuit board which results in an undesirably large printed circuit board (about 3.75 inches by 3.5 inches for over 13 square inches).
Still another disadvantage of the known printing station is that the rasterizer board has a microprocessor-based architecture for driving software that results in very slow data processing that is only fast enough to achieve image resolutions of about 300 dots per inch.
Still another disadvantage of the known printing station is that the pens are affixed with screws to the pen housing and not easily removed for replacement or cleaning. In a production printing environment, the printing station may be used to print addresses on envelopes where the pens may be used to print 200 or more images per minute (or 12,000 or more images per hour). In such an environment, the pens must be changed frequently and as quickly as possible to avoid unnecessary printing station down time, which results in less envelope being printed per minute.
Still another disadvantage of the known printing station is that the pen is affixed with screws to a pen housing of the printing station, and thus not easily removed for servicing the pen driver boards or changing the pens.
The present invention is designed to overcome the above disadvantages that are attendant upon the use of the xe2x80x9cprior artxe2x80x9d printing station.
The present invention provides an imager having a service station assembly with a customized interface board, and also having a cartridge assembly with a customized rasterizer board and one or more customized pen driver boards.
The customized interface board has a controller that responds to an image signal containing an image to be printed on a medium, the image signal having any one of a number of different standard interface, for providing an interface board image signal in a protocol suitable for the customized rasterizer board. The image signal may contain information in the form of ASCII text, bitmaps, logos, indicia, graphics, bar codes; etc. The medium may include paper, packages, textiles, labels, calenders, passports, etc.
The customized rasterizer board has a programmable logic device (i.e. firmware), responds to the interface board image signal, rasterizes the interface board image signal into a bitmap, and provides a customized rasterizer board image signal.
The one or more customized pen driver boards have a programmable logic device (i.e. firmware), respond to the customized rasterizer board image signal, remap the customized rasterizer board image signal, and provide a pen driver board signal to a corresponding one or more pens for printing the image on the medium.
The cartridge assembly has one or more cartridge channels for receiving the one or more pens, and one or more clamping assembles for pivotally engaging and detachably latching the one or more pens in the one or more cartridge channels.
The service station assembly has a vertical bracket with channels. The cartridge assembly has tongues for sliding into the channels for slidably mounting the cartridge assembly and the service station assembly.
One advantage of the present invention is that the customized interface board may include many different standard interfaces, including an RS232 interface, RS845 interface, a parallel printer port interface, USB interface, or ethernet interface, and daisy chains multiple imagers.
Another advantage of the present invention is that the customized rasterizer board is included in the cartridge assembly. This reduces the electrical noise from being introduced into the rasterized image signal transmitted from the customized rasterizer board to the customized pen driver board, which is a high frequency signal. The customized rasterizer board can be arranged in the pen housing because it is configured from a customized printed circuit board which uses a high density board having multiple layers (i.e. for example 6 or more different layers with tracers) that results in a much smaller compact printed circuit board (about 3.5 inches by 2.75 inches for less than 10 square inches). The high density board, multi-layered approach translates into a space savings in square inches of about 30%, which provides a highly modularized imager design that is much more readily adaptable for many different types of printing station applications including an ATM machine, a point of sale terminal, gas pumps, etc. Similarly, the pen driver board is configured on a customized printed circuit board which uses a high density board having multiple layers.
Still another advantage of the present invention is that the programmable logic device (i.e. firmware) in the customized rasterizer board is fast and able to process data fast enough to achieve image resolutions greater than 600 dots per inch, which is four times (4xc3x97) the image resolution of the prior art printing station (i.e. 300 dots per inch). Similarly, the customized pen driver board has a programmable logic device (i.e. firmware) that is fast and able to process data fast enough to achieve image resolutions greater than 600 dots per inch.
Still another advantage of the present invention is that the one or more pens are attached to the pen housing by a pivot latch and easily removed for replacement or cleaning. In a production printing environment, the pens can be quickly changed to avoid any unnecessary printing down time, which results in more envelopes being printed per minute on the average.
Still another advantage of the present invention is that the cartridge assembly is slidably mounted on the service station assembly, thus easily removed for servicing the cartridge assembly, changing the one or more pens, or cleaning the one or more pens by wiping. In a production printing environment, the one or more pens will have to be cleaned numerous times in the course of a day.
The invention will be fully understood when reference is made to the following detailed description taken in conjunction with the accompanying drawings.